I. Field of the Invention
This invention pertains to collating or insertion machines, and particularly to such machines wherein a group of related items are stuffed or inserted into a packaging medium such as an envelope.
II. Prior Art and Other Considerations
In a conventional insertion machine, series of related items, such as documents commonly referred to as "inserts", are associated together and inserted or "stuffed" into an awaiting, flap-opened envelope. Thereafter the stuffed envelope is sealed and various other operations can be performed, such as associating the stuffed envelopes with an appropriate postage weight category and/or grouping or sorting by zip code or in accordance with other criteria.
In a very popular type of insertion machine, an envelope and insert are respectively transported to an insertion station on two parallel tracks or conveyors, namely an insert track provided on a machine back table and an envelope track provided on a machine front table. Typically these tracks are indexed in a direction toward the insertion station in accordance with a machine cycle, e.g. with the track advancing essentially one track space toward the insertion station for every one revolution of a machine main timing shaft.
The insert track for the type of machine being described traditionally comprises a pair of endless chains which travel alongside a series of feeder stations. Each chain has a plurality of pusher pins provided thereon for causing inserts fed onto the chain pair to be driven in the direction toward the insertion station in accordance with machine timing.
An example of the type of insertion machine briefly described above is shown in U.S. Pat. No. 2,325,455 to A. H. Williams. Despite their mechanical intricacies, modern insertion machines of this type have amazing throughput and operate at very high speeds on the order of about 10,000 cycles per hour. It is a remarkable feat, for example, that by coordinated mechanical action, an insertion machine can extract an item from a hopper; deposit the extracted item onto the insert track; and index the item to the vicinity of another downstream insert station with such rapidity. Yet, as the mailings prepared by such entities as financial institutions, utilities, governmental bodies and direct mail concerns continue to proliferate, it is evident that machines of comparable function but with even faster operational speeds would be welcome. Hence, an object of this invention is the provision of an insertion machine capable of high operating speeds.
In order to operate an insertion machine at very high operating speeds such as in excess of 10,000 cycles per hour, the structure and composition of the insert track must not impose limitations nor impede rapid travel of groups of items therealong in the direction of the insertion station. Accordingly, an advantage of the present invention is the provision of an insertion machine wherein an insert track is fabricated from materials that facilitate rapid indexing of groups of items therealong.
The operation of an insertion machine at very high operating speeds poses significant problems relative to paper handling and placement. For example, the greater the speed with which an item is extracted from an insert station hopper and then released proximate the insert track, the greater the inertia possessed by the released item. If an item has significant inertia upon release, the item may not be precisely positioned on the insert track in a manner conducive to continued processing. While prior art insertion machines have employed "ski"-like members mounted on the front edge of the insert track to direct released items toward the insert track, such members have, on some occasion, interferred with the placement of items on the insert track. Hence, another advantage of the present invention is the provision of method and apparatus for controlling the inertia of a released item to facilitate precise placement of the item on the insert track.
Another example of problems associated with high speed paper handling is the tendency of edge portions of an item extracted from a hopper by a feeder to act as an airfoil and to "wing" upwardly. Such behavior further complicates the challenge to precisely place the item on the insert track, since the winged item has the potential of "flying" upon release. Accordingly, another advantage of the present invention is the provision of method and apparatus for preventing the deformation of items fed fron an insert station hopper.
Yet another complication with high speed paper handling in an insertion machine is the difficulty in aligning the upstream edges of related but differently sized items once the items have been fed on top of one another on the insert track. Hence, a further advantage of the present invention is the provision of method and apparatus for aligning related items fed onto the insert track in a manner such that, once aligned, related items in a group can uniformly be imparted momentum as the insert track is indexed.
Insert tracks must be of selectively variable width in order to accommodate items of different sizes being handled from job to job. Thus, a yet further advantage of the present invention is the provision of an insert track having an easily and selectively adjustable width.